Dynamic constant folding of a circuit

Abstract

The present invention provides a method involving at least one first circuit having at least one first input, at least one second input, and at least one output. The method includes determining at least one first value of at least one output of a second circuit based on at least one first value of the at least one first input. The second circuit has been configured using first configuration information generated based on the first circuit and at least one first value of the at least one second input. The method also includes generating, concurrently with determining the at least one first value of said at least one output, second configuration information based on the first circuit and at least one second value of the at least one second input.

1. A method of operating a constant-folded circuit that is representative of at least one first circuit having at least one first input that varies on a relatively short time scale, at least one second input that varies on a relatively long time scale, and at least one output, comprising:
 determining at least one first value of at least one output of the constant-folded circuit based on at least one first value of said at least one first input, the constant-folded circuit having been configured using first configuration information generated based on the first circuit and a plurality of possible values of said at least one first input, at least one first value of said at least one second input, and at least one first value of the output corresponding to the values of the first and second inputs; and 
 generating, concurrently with determining said at least one first value of said at least one output, second configuration information for the constant-folded circuit based on the first circuit and the plurality of possible values of said at least one first input, at least one second value of said at least one second input, and at least one second value of the output corresponding to the values of the first and second inputs. 
 
   
   
     2. The method of  claim 1 , wherein said at least one first value of said at least one output of the constant-folded circuit corresponds to at least one value of said at least one output of the first circuit that would be generated by the first circuit in response to said at least one first value of said at least one first input and said at least one first value of said at least one second input. 
   
   
     3. The method of  claim 1 , wherein generating the second configuration information comprises generating the second configuration information using at least one generator function corresponding to the at least one first circuit. 
   
   
     4. The method of  claim 3 , wherein generating the second configuration information using said at least one generator function corresponding to said at least one first circuit comprises generating a lookup table using said at least one generator function. 
   
   
     5. The method of  claim 4 , wherein generating the lookup table using said at least one generator function comprises generating a plurality of entries in the lookup table using said at least one generator function, said at least one second value of said at least one second input, and the plurality of possible values of said at least one first input. 
   
   
     6. The method of  claim 1 , comprising providing the second configuration information to a configuration memory associated with the constant-folded circuit. 
   
   
     7. The method of  claim 6 , wherein providing the second configuration information to the configuration memory comprises providing the second configuration information to the configuration memory concurrently with determining said at least one first value of said at least one output of the constant-folded circuit. 
   
   
     8. The method of  claim 6 , comprising modifying at least one location of a portion of the first configuration information in the configuration memory in response to providing a portion of the second configuration information to the configuration memory. 
   
   
     9. The method of  claim 1 , comprising determining at least one second value of at least one output of the constant-folded circuit based on at least one second value of said at least one first input. 
   
   
     10. The method of  claim 9 , comprising generating, concurrently with determining said at least one second value of said at least one output of the constant-folded circuit, third configuration information using said at least one generator function corresponding to said at least one first circuit and at least one third value of said at least one second input. 
   
   
     11. A method involving a matched filter comprising at least one correlator that operates as a constant-folded circuit configured to correlate code sequences with a portion of a data stream that remains constant during a search window, comprising:
 determining at least one first correlation value based on the portion of the code sequence and a first portion of the data stream using the correlator, the correlator having been configured using first configuration information generated based on the first portion of the data stream, the determination been performed during the search window; and 
 generating, concurrently with determining said at least one first correlation value, second configuration information based on a second portion of the data stream. 
 
   
   
     12. The method of  claim 11 , wherein determining said at least one first correlation value comprises determining a plurality of first correlation values based on the portion of the code sequence and a plurality of first portions of the data stream using a plurality of correlators, each of the plurality of correlators having been configured using a plurality of first configuration information sets generated based on a corresponding one of the plurality of first portions of the data stream. 
   
   
     13. The method of  claim 12 , wherein generating the second configuration information comprises generating, concurrently with determining the plurality of first correlation values, a plurality of second configuration information sets based on a plurality of second portions of the data stream. 
   
   
     14. The method of  claim 11 , wherein generating the second configuration information comprises generating the second configuration information using at least one generator function corresponding to the correlator. 
   
   
     15. The method of  claim 14 , wherein generating the second configuration information using said at least one generator function corresponding to said at least one first circuit comprises generating at least one lookup table using said at least one generator function. 
   
   
     16. The method of  claim 15 , wherein generating said at least one lookup table using said at least one generator function comprises generating a plurality of entries in said at least one lookup table using said at least one generator function, said portion of the data stream, and a plurality of values of the portion of the code sequence. 
   
   
     17. The method of  claim 11 , comprising providing the second configuration information to a configuration memory associated with the correlator. 
   
   
     18. The method of  claim 17 , wherein providing the second configuration information to the configuration memory comprises providing the second configuration information to the configuration memory concurrently with determining said at least one first correlation value. 
   
   
     19. The method of  claim 17 , comprising modifying at least one location of a portion of the first configuration information in the configuration memory in response to providing the portion of the second configuration information to the configuration memory. 
   
   
     20. The method of  claim 11 , comprising determining at least one second correlation value based on a second portion of the data stream. 
   
   
     21. The method of  claim 20 , comprising generating, concurrently with determining said at least one second correlation value, third configuration information using said at least one generator function based on a third portion of the data stream.